1. Field of the Invention
The present invention relates to an active roll control system for a vehicle. More particularly, the present invention relates to an active roll control system for a vehicle which can actively control roll stiffness in accordance with traveling conditions of the vehicle.
2. Description of the Related Art
Vehicles are equipped with a suspension between the car shaft and the car body to achieve riding comfort and traveling stability by reducing vibration and impact from the road in traveling.
Therefore, the suspension is required to smoothly absorb vibrations, such as bounce, rolling, pitching, and yawing of a car body, which are generated in traveling, in order to ensure riding comfort and traveling stability.
In order to achieve the function described above, the suspension of vehicles includes a spring attenuating impact transmitted from the road, a shock absorber improving riding comfort by controlling the free vibration of the spring, and a stabilizer bar minimizing rolling of the vehicle turning.
The stabilizer bar relating to the present invention is a kind of torsion spring that maintains balance of the car body by suppressing roll motion of the car body in turning or traveling on a rough road.
In the arrangement of the stabilizer bar, as shown in FIG. 1, lower control rams 8 and 10 or strut assemblies 12 and 14 are connected by disposing stabilizer links 4 and 6 at both ends, and both straight portions are fixed by disposing mount bushes 18 and 20 on a sub-frame 16.
The stabilizer bar 2 described above functions as a sub-spring supporting the left and right wheels in rolling of the vehicle, and suppresses the roll motion of the car body by restricting the left and right wheel with torsional elasticity when the left and right wheels move in the inverse phase, without receiving force when the left and right wheels move in the same phase.
For example, the suspension suppresses inclination of the car body by making both wheels in the same movement when the outer wheels bounce and the inner wheels rebound, in turning, while it does not work when the left and right wheels simultaneously move in the same direction.
However, when a stabilizer is disposed, as described above, the stabilizer bar has small spring characteristics to improve riding comfort, but it is difficult to suppress rolling due to the centrifugal force in turning, while when the spring characteristics of the stabilizer bar is increased, it operates like a fixed axle and reduces the riding comfort.
Further, the stabilizer bar described above has one limited spring characteristic, such that it is impossible to actively control various roll motions generated in turning and it makes the turning unstable, and particularly, it is very unstable in turning at a high speed.
The information disclosed in this Background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.